Magnetic and Electrical Transport Properties of YbFe₂O₄

We present magnetic properties, Mössbauer, resistivity, magnetoresistance, and dielectric properties of a polycrystalline YbFe₂O₄ prepared by an electron-beam assisted solid state reaction. The ferrimagnetic transition temperature of YbFe₂O₄ was measured at 242 K, followed by the two low-temperature transitions at ~200 K and 70 K, respectively. The M-H hysteresis loops exhibit a strong temperature dependence with the strongest coercive field and residual magnetization at ~100 K. The temperature dependence of the magnetic properties suggests that YbFe₂O₄ has a complex magnetic phase below 100 K. Room temperature Mossbauer measurement indicates the presence of Fe²⁺ and Fe³⁺ ions in the sample. Resistivity of YbFe₂O₄ has been analyzed based on Mott’s variable-range hopping model. The magnetoresistance effects in the ferrimagnetic state were observed and the effects could be attributed to the field-induced changes in the electron hopping processes. We also discuss the temperature and frequency dependence of the dielectric constant of YbFe₂O₄, which were found to be strongly influenced by the contact effects, indicating no evidence of the intrinsic ferroelectricity.